Only an individual who itemizes deductions on the individual’s federal income tax return may elect to itemize deductions on the individual’s income tax return. Subject to subsection (c) of this section, an individual who elects to itemize deductions is allowed as a deduction the sum of the individual’s federal itemized deductions: limited and reduced as required under the Internal Revenue Code; further reduced by any amount deducted under § 170 of the Internal Revenue Code for contributions of a preservation or conservation easement for which a credit is claimed under § 10–723 of this title; and further reduced by the amount claimed as taxes on income paid to a state or political subdivision of a state, after subtracting a pro rata portion of the reduction to itemized deductions required under § 68 of the Internal Revenue Code. In this subsection, “applicable amount” means: $100,000 for a married individual filing separately; and $200,000 for all other filers. This subsection does not apply to a fiduciary. In the case of an individual whose federal adjusted gross income exceeds the applicable amount, the amount of itemized deductions otherwise allowable for a taxable year shall be reduced by 7.5% of the excess of the federal adjusted gross income over the applicable amount. This subsection shall be applied after the application of any other limitation on the allowance of any itemized deduction.